1. Field of the Invention
This invention relates to apparatus for controlling the operation of tambour doors, and in particular to such apparatus using a spring for controlling the opening and closing of tambour doors.
2. Related Art
Appliance garages now on the market rely upon a track to guide the tambour door into a storage area above the door opening. This track is often made of plastic and is fastened to the door frame. A problem with such a design is the difficulty in making the unit slide easily in the track and still not free-fall as the tambour door is moving through the doorway.
The problem of free-falling can be eliminated in various ways, such as by a friction lock mounted in the tambour door to hold it in position, or by some other means of counter-balancing the weight of the tambour door.
Other designs counterbalance the tambour door via a spring, mounted to coil tighter as the door is closed. The principle of this design is a step forward in eliminating the free-falling door, although it also imposes a problem. The coil spring must be matched to the tambour door weight very closely, and therefore requires an adjustment in tension by the installer. The change in tambour door weight as it is closed will only match one spring rate relative to a particular door width. For a wider tambour door, a different spring rate is required. To minimize the tambour door from moving up by itself, a friction latch is employed at the end of the track to engage the door when it is fully closed.